feat: override options by format

Author: sxzz

docs/options/output-format.md

@@ -6,7 +6,7 @@ By default, `tsdown` generates JavaScript code in the [ESM](https://nodejs.org/a
 tsdown --format esm # default
 ```
 
-### Available Formats
+## Available Formats
 
 - [`esm`](https://nodejs.org/api/esm.html): ECMAScript Module format, ideal for modern JavaScript environments, including browsers and Node.js.
 - [`cjs`](https://nodejs.org/api/modules.html): CommonJS format, commonly used in Node.js projects.
@@ -28,3 +28,23 @@ tsdown --format iife
 
 > [!TIP]
 > You can specify multiple formats in a single command to generate outputs for different environments. For example, combining `esm` and `cjs` ensures compatibility with both modern and legacy systems.
+
+## Overriding Configuration by Format
+
+You can override specific configuration options for each output format by setting `format` as an object in your config file. This allows you to tailor settings such as `target` or other options for each format individually.
+
+```ts
+export default defineConfig({
+  entry: ['./src/index.js'],
+  format: {
+    esm: {
+      target: ['es2015'],
+    },
+    cjs: {
+      target: ['node20'],
+    },
+  },
+})
+```
+
+In this example, the ESM output will target ES2015, while the CJS output will target Node.js 20. This approach gives you fine-grained control over the build process for different module formats.

docs/zh-CN/options/output-format.md

@@ -6,7 +6,7 @@
 tsdown --format esm # 默认
 ```
 
-### 可用格式
+## 可用格式
 
 - [`esm`](https://nodejs.org/api/esm.html)：ECMAScript 模块格式，适用于包括浏览器和 Node.js 在内的现代 JavaScript 环境。
 - [`cjs`](https://nodejs.org/api/modules.html)：CommonJS 格式，常用于 Node.js 项目。
@@ -28,3 +28,23 @@ tsdown --format iife
 
 > [!TIP]
 > 您可以在单个命令中指定多个格式，以生成适用于不同环境的输出。例如，结合使用 `esm` 和 `cjs` 格式可以确保同时兼容现代和传统系统。
+
+## 按格式覆盖配置
+
+您可以在配置文件中将 `format` 设置为对象，从而为每种输出格式单独覆盖特定配置选项。这允许您为每个格式分别定制如 `target` 等设置。
+
+```ts
+export default defineConfig({
+  entry: ['./src/index.js'],
+  format: {
+    esm: {
+      target: ['es2015'],
+    },
+    cjs: {
+      target: ['node20'],
+    },
+  },
+})
+```
+
+在此示例中，ESM 输出将以 ES2015 为目标，CJS 输出将以 Node.js 20 为目标。通过这种方式，您可以对不同模块格式的构建过程进行精细化控制。

src/config/options.ts

@@ -11,6 +11,7 @@ import { resolveTsconfig } from '../features/tsconfig.ts'
 import {
   matchPattern,
   pkgExists,
+  resolveComma,
   resolveRegex,
   toArray,
 } from '../utils/general.ts'
@@ -20,6 +21,7 @@ import type { Awaitable } from '../utils/types.ts'
 import { loadViteConfig } from './file.ts'
 import type {
   CIOption,
+  Format,
   InlineConfig,
   ResolvedConfig,
   UserConfig,
@@ -259,15 +261,23 @@ export async function resolveUserConfig(
     write,
   }
 
-  return normalizeFormat(format).map((format, idx): ResolvedConfig => {
+  const objectFormat = typeof format === 'object' && !Array.isArray(format)
+  const formats = objectFormat
+    ? (Object.keys(format) as Format[])
+    : resolveComma(toArray<Format>(format, 'es'))
+  return formats.map((fmt, idx): ResolvedConfig => {
     const once = idx === 0
+    const overrides = objectFormat ? format[fmt] : undefined
     return {
       ...config,
-      format,
       // only copy once
       copy: once ? config.copy : undefined,
       // don't register hooks repeatedly
       hooks: once ? config.hooks : undefined,
+      // only execute once
+      onSuccess: once ? config.onSuccess : undefined,
+      format: normalizeFormat(fmt),
+      ...overrides,
     }
   })
 }

src/config/types.ts

@@ -257,7 +257,7 @@ export interface UserConfig {
   //#region Output Options
 
   /** @default 'es' */
-  format?: Format | Format[]
+  format?: Format | Format[] | Partial<Record<Format, Partial<ResolvedConfig>>>
   globalName?: string
   /** @default 'dist' */
   outDir?: string
@@ -393,13 +393,6 @@ export interface UserConfig {
    */
   ignoreWatch?: Arrayable<string | RegExp>
 
-  /**
-   * You can specify command to be executed after a successful build, specially useful for Watch mode
-   */
-  onSuccess?:
-    | string
-    | ((config: ResolvedConfig, signal: AbortSignal) => void | Promise<void>)
-
   /**
    * **[experimental]** Enable debug mode.
    *
@@ -413,6 +406,13 @@ export interface UserConfig {
 
   //#region Addons
 
+  /**
+   * You can specify command to be executed after a successful build, specially useful for Watch mode
+   */
+  onSuccess?:
+    | string
+    | ((config: ResolvedConfig, signal: AbortSignal) => void | Promise<void>)
+
   /**
    * Enables generation of TypeScript declaration files (`.d.ts`).
    *

src/utils/package.ts

@@ -2,7 +2,6 @@ import { readFile } from 'node:fs/promises'
 import { up as findPackage } from 'empathic/package'
 import { createDebug } from 'obug'
 import type { Format, NormalizedFormat } from '../config/index.ts'
-import { resolveComma, toArray } from './general.ts'
 import type { PackageJson } from 'pkg-types'
 
 const debug = createDebug('tsdown:package')
@@ -34,20 +33,16 @@ export function getPackageType(pkg: PackageJson | undefined): PackageType {
   }
 }
 
-export function normalizeFormat(format: Format | Format[]): NormalizedFormat[] {
-  return resolveComma(toArray<Format>(format, 'es')).map(
-    (format): NormalizedFormat => {
-      switch (format) {
-        case 'es':
-        case 'esm':
-        case 'module':
-          return 'es'
-        case 'cjs':
-        case 'commonjs':
-          return 'cjs'
-        default:
-          return format
-      }
-    },
-  )
+export function normalizeFormat(format: Format): NormalizedFormat {
+  switch (format) {
+    case 'es':
+    case 'esm':
+    case 'module':
+      return 'es'
+    case 'cjs':
+    case 'commonjs':
+      return 'cjs'
+    default:
+      return format
+  }
 }